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<head><meta charset="utf-8"><title>crater run · edition 2021 · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/index.html">edition 2021</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html">crater run</a></h3>

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<a name="246084831"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246084831" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246084831">(Jul 15 2021 at 12:11)</a>:</h4>
<p>I'm uncertain, my understanding is that crater is only designed to compare two toolchains.  It seems like for testing the edition, it needs to run different commands against "start" vs " end".   I'm not sure if crater has the ability to do that.  Just running <code>cargo fix</code> with two different toolchains isn't going to provide any information.  Does crater have the ability to do that?</p>



<a name="246085525"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246085525" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246085525">(Jul 15 2021 at 12:19)</a>:</h4>
<p>In the past, to do this, what I have done is create a custom Cargo that runs the commands I want.  That is, one could run crater in "check" mode, and have a custom cargo that when it runs <code>cargo check</code>, it actually runs something else (like <code>cargo fix --edition</code>, modify edition, <code>cargo check</code>).  That way, the "start" runs a normal check (to get a baseline), and then the "end" can do all the magic.</p>



<a name="246103398"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103398" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103398">(Jul 15 2021 at 14:37)</a>:</h4>
<p><span class="user-mention" data-user-id="120518">@Eric Huss</span> that makes a lot of sense</p>



<a name="246103591"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103591" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103591">(Jul 15 2021 at 14:38)</a>:</h4>
<p>Is cargo built from rust-lang/rust?</p>



<a name="246103601"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103601" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103601">(Jul 15 2021 at 14:38)</a>:</h4>
<p>(when we do a crater run)</p>



<a name="246103614"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103614" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103614">(Jul 15 2021 at 14:38)</a>:</h4>
<p>i.e., can you make a single PR that encapsulates the change to cargo?</p>



<a name="246103626"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103626" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103626">(Jul 15 2021 at 14:38)</a>:</h4>
<p>(cc <span class="user-mention" data-user-id="121055">@Pietro Albini</span>)</p>



<a name="246103674"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103674" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103674">(Jul 15 2021 at 14:39)</a>:</h4>
<p>Yes.</p>



<a name="246103723"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103723" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103723">(Jul 15 2021 at 14:39)</a>:</h4>
<p>I can probably put something together.  It shouldn't be too hard.</p>



<a name="246103733"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103733" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103733">(Jul 15 2021 at 14:39)</a>:</h4>
<p>Much easier than changing crater.</p>



<a name="246103768"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103768" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103768">(Jul 15 2021 at 14:39)</a>:</h4>
<p>Yes, we should do that</p>



<a name="246103784"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103784" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103784">(Jul 15 2021 at 14:39)</a>:</h4>
<p>It seems like the <em>ideal</em> would be to land a patch in cargo</p>



<a name="246103861"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103861" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103861">(Jul 15 2021 at 14:40)</a>:</h4>
<p>such that this experiment is easy to repeat in the future</p>



<a name="246103889"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103889" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103889">(Jul 15 2021 at 14:40)</a>:</h4>
<p>but maybe we get it working first, and then try to do that?</p>



<a name="246103979"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246103979" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246103979">(Jul 15 2021 at 14:41)</a>:</h4>
<p>(I'm imagining e.g. landing most of the patch, such that it's a 1-line diff to re-enable later or something...)</p>



<a name="246105763"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246105763" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Pietro Albini <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246105763">(Jul 15 2021 at 14:54)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/268952-edition-2021/topic/crater.20run/near/246103591">said</a>:</p>
<blockquote>
<p>Is cargo built from rust-lang/rust?</p>
</blockquote>
<p>it should, if it doesn't it's really easy to fix that</p>



<a name="246221853"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246221853" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246221853">(Jul 16 2021 at 13:24)</a>:</h4>
<p>I have a custom cargo ready to go.  When do we want to do the crater run?</p>



<a name="246222254"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246222254" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> rylev <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246222254">(Jul 16 2021 at 13:27)</a>:</h4>
<p>I was hoping we could land a fix for <a href="https://github.com/rust-lang/rust/issues/86940">https://github.com/rust-lang/rust/issues/86940</a>. It's been claimed, but we're unsure when it will be fixed.</p>



<a name="246248179"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246248179" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246248179">(Jul 16 2021 at 16:44)</a>:</h4>
<p>That's awesome</p>



<a name="246268786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246268786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246268786">(Jul 16 2021 at 19:36)</a>:</h4>
<p>Hm, looks like there will be an issue with crater. It mounts the filesystem as read-only, but <code>cargo fix</code> needs to be able to modify the sources.  <span class="user-mention" data-user-id="121055">@Pietro Albini</span> Is there a feasible workaround?  Would it be horrible to have my custom script copy the workdir to <code>/tmp</code> or something like that?</p>



<a name="246269665"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246269665" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Pietro Albini <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246269665">(Jul 16 2021 at 19:44)</a>:</h4>
<p>ugh changing that could be tricky</p>



<a name="246269728"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246269728" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Pietro Albini <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246269728">(Jul 16 2021 at 19:45)</a>:</h4>
<p>and double ugh you need to run <code>cargo fix</code> inside the sandbox don't you</p>



<a name="246269802"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246269802" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246269802">(Jul 16 2021 at 19:46)</a>:</h4>
<p>Yea.</p>



<a name="246269922"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246269922" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246269922">(Jul 16 2021 at 19:47)</a>:</h4>
<p>Hey, maybe you can answer a quick question re crater.  Every time I run it, it downloads stable and rebuilds rustup-toolchain-install-master, which for me takes a few minutes.  Is there a way to avoid that?</p>



<a name="246270059"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246270059" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Pietro Albini <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246270059">(Jul 16 2021 at 19:48)</a>:</h4>
<p>it... shouldn't?</p>



<a name="246270073"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246270073" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Pietro Albini <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246270073">(Jul 16 2021 at 19:48)</a>:</h4>
<p>are you deleting the workspace?</p>



<a name="246270126"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246270126" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246270126">(Jul 16 2021 at 19:49)</a>:</h4>
<p>I run <code>delete-all-results</code> and then <code>run-graph</code>, and it downloads again.</p>



<a name="246270149"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246270149" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246270149">(Jul 16 2021 at 19:49)</a>:</h4>
<p>No worries, I can try to investigate a little.  I'm still struggling just to understand how things work. <span aria-label="grinning" class="emoji emoji-1f600" role="img" title="grinning">:grinning:</span></p>



<a name="246270776"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246270776" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Pietro Albini <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246270776">(Jul 16 2021 at 19:55)</a>:</h4>
<p>it... shouldn't do that?</p>



<a name="246270795"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246270795" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Pietro Albini <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246270795">(Jul 16 2021 at 19:55)</a>:</h4>
<p>can you paste the full logs somewhere?</p>



<a name="246281511"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246281511" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246281511">(Jul 16 2021 at 21:18)</a>:</h4>
<p>OK, I got my hacked <code>cargo fix</code> working with crater, so it should be ready to go whenever we're ready.  I tested with a demo crate containing <a href="https://github.com/rust-lang/rust/issues/86940">#86940</a> and it properly reported a regression.</p>
<p>Here is what the hack looks like: <a href="https://github.com/ehuss/cargo/commit/e32d9d54c8dfbe0c890cb88c327e22d05399313c">https://github.com/ehuss/cargo/commit/e32d9d54c8dfbe0c890cb88c327e22d05399313c</a></p>
<p>I also did a short run against a few real crates, and things seemed to work as expected. It did find one regression. <code>non-fmt-panics</code> is a <code>MaybeIncorrect</code> suggestion, so it fails to migrate (found while migrating <code>structopt</code>). Is that a known issue? I can't find any related to that.</p>



<a name="246283708"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246283708" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246283708">(Jul 16 2021 at 21:39)</a>:</h4>
<p>Oh, another question. My hack ignores 2015 packages. That can make the report look a little odd (if a 2015 fails during the first round, it will succeed in the second, appearing to be "fixed"). I'm thinking we can just ignore those in the report, does that sound reasonable?</p>



<a name="246308037"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246308037" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246308037">(Jul 17 2021 at 06:18)</a>:</h4>
<p><span class="user-mention" data-user-id="120518">@Eric Huss</span> that sounds great! I agree we can ignore those.</p>



<a name="246449097"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246449097" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Mara <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246449097">(Jul 19 2021 at 12:40)</a>:</h4>
<p><span class="user-mention silent" data-user-id="120518">Eric Huss</span> <a href="#narrow/stream/268952-edition-2021/topic/crater.20run/near/246281511">said</a>:</p>
<blockquote>
<p>I also did a short run against a few real crates, and things seemed to work as expected. It did find one regression. <code>non-fmt-panics</code> is a <code>MaybeIncorrect</code> suggestion, so it fails to migrate (found while migrating <code>structopt</code>). Is that a known issue? I can't find any related to that.</p>
</blockquote>
<p>It should produce both a MaybeIncorrect and a MachineApplicable suggestion as alternatives. <code>cargo fix --edition</code> should just pick the latter. Did that not happen?</p>



<a name="246449676"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246449676" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Mara <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246449676">(Jul 19 2021 at 12:46)</a>:</h4>
<p>ah, it happened in the panic!() insider assert!(). yeah. that one doesn't have a MachineApplicable suggestion. the only always correct suggestion would be <code>if !... { std::panic::panic_any(...); }</code> which isn't great. :/</p>



<a name="246450855"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246450855" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246450855">(Jul 19 2021 at 12:58)</a>:</h4>
<p><span class="user-mention silent" data-user-id="120518">Eric Huss</span> <a href="#narrow/stream/268952-edition-2021/topic/crater.20run/near/246283708">said</a>:</p>
<blockquote>
<p>Oh, another question. My hack ignores 2015 packages. That can make the report look a little odd (if a 2015 fails during the first round, it will succeed in the second, appearing to be "fixed"). I'm thinking we can just ignore those in the report, does that sound reasonable?</p>
</blockquote>
<p>I did have a question about this, why do 2015 crates fail in the first round-- oh, because we ignore them <em>entirely</em>? Can we just fallback to the "normal" behavior for 2015 crates instead, so that they show up as having the same result?</p>



<a name="246464571"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246464571" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246464571">(Jul 19 2021 at 14:49)</a>:</h4>
<p>Short answer: I didn't want to waste the cycles running <code>cargo check</code> just to align the results.</p>
<p>The issue is if a 2015 crate fails <code>cargo check</code> with the first toolchain (for unrelated reasons), the second toolchain doesn't know that.  It could run <code>cargo check</code> again, just so the results line up, but I figured that would be a waste of cycles, so it just exits immediately with "success".   There should be a relatively small set of packages that are 2015, and fail to compile <em>at all</em>.  Also, I seem to recall that crater eventually removes packages that never build, is that true?</p>
<p>It could also migrate from 2015 &gt; 2021, but I figure the 2018 migration bugs would just cause too much noise.</p>



<a name="246465143"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246465143" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246465143">(Jul 19 2021 at 14:53)</a>:</h4>
<p><span class="user-mention silent" data-user-id="310399">Mara</span> <a href="#narrow/stream/268952-edition-2021/topic/crater.20run/near/246449676">said</a>:</p>
<blockquote>
<p>ah, it happened in the panic!() insider assert!(). yeah. that one doesn't have a MachineApplicable suggestion. the only always correct suggestion would be <code>if !... { std::panic::panic_any(...); }</code> which isn't great. <span aria-label="confused" class="emoji emoji-1f615" role="img" title="confused">:confused:</span></p>
</blockquote>
<p>Should I file an issue for this?</p>



<a name="246616114"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/246616114" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#246616114">(Jul 20 2021 at 16:33)</a>:</h4>
<p>I went ahead and filed <a href="https://github.com/rust-lang/rust/issues/87313">https://github.com/rust-lang/rust/issues/87313</a> to track the <code>assert!</code> problem.  I don't know if there are any practical options here.  Since <code>non_fmt_panics</code> has been warning for a while, I would assume most projects will have already cleaned it up, so perhaps automatic migration is not very important.</p>



<a name="247207403"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247207403" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247207403">(Jul 26 2021 at 14:13)</a>:</h4>
<p>Do ya'll have any thoughts on when you want to start the crater run?</p>



<a name="247214888"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247214888" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247214888">(Jul 26 2021 at 15:03)</a>:</h4>
<p>Good question. My thought is that it makes sense to let the public testing period run for a week or so?</p>



<a name="247214902"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247214902" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247214902">(Jul 26 2021 at 15:03)</a>:</h4>
<p>I'd like to at minimum patch up the known bugs</p>



<a name="247930808"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247930808" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> rylev <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247930808">(Aug 02 2021 at 15:09)</a>:</h4>
<p><span class="user-mention" data-user-id="120518">@Eric Huss</span> We've reached the week or so threshold and <span class="user-mention" data-user-id="310399">@Mara</span> and I looked at the bugs and none seemed to be crater blocking. How do we kick off the crater run?</p>



<a name="247930901"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247930901" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247930901">(Aug 02 2021 at 15:10)</a>:</h4>
<p>I'll rebuild my PR.  I don't have permission to run crater.  I'll either get myself added, or find someone who does.</p>



<a name="247930934"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247930934" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247930934">(Aug 02 2021 at 15:10)</a>:</h4>
<p>I want to run a small test (like top 1000) just to make sure it is working correctly.</p>



<a name="247930937"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247930937" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Mara <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247930937">(Aug 02 2021 at 15:10)</a>:</h4>
<p>i have. just link me the PR</p>



<a name="247930946"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247930946" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247930946">(Aug 02 2021 at 15:10)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="247955217"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247955217" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247955217">(Aug 02 2021 at 18:50)</a>:</h4>
<p><span class="user-mention" data-user-id="310399">@Mara</span>, the PR is <a href="https://github.com/rust-lang/rust/pull/87190">https://github.com/rust-lang/rust/pull/87190</a>.  I think the command I want is <code>@craterbot check crates=top-1000</code></p>



<a name="247955236"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247955236" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Mara <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247955236">(Aug 02 2021 at 18:50)</a>:</h4>
<p>just <code>check</code>?</p>



<a name="247955301"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247955301" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247955301">(Aug 02 2021 at 18:51)</a>:</h4>
<p>Yea, it has an custom <code>cargo</code> that will run <code>cargo fix</code>, and then <code>cargo check</code> afterwards.  I don't think doing a full test is necessary, do you?</p>



<a name="247955580"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247955580" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Mara <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247955580">(Aug 02 2021 at 18:53)</a>:</h4>
<p>yeah good question. i don't think we'd cause many run-time changes. but maybe the closure capture thing or panics might cause some run-time behaviour to change? but we'd have to be lucky for it to actually be tested by some crate.</p>



<a name="247955948"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247955948" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eric Huss <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247955948">(Aug 02 2021 at 18:57)</a>:</h4>
<p>Yea, that's definitely possible.  My understanding is that a <code>test</code> run takes quite a lot longer than a <code>check</code> run, is that correct?  I think it would be valuable to do some quick check runs first to see how things go, and then we can consider doing a <code>test</code> run later if desired.</p>



<a name="247956034"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247956034" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Mara <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247956034">(Aug 02 2021 at 18:57)</a>:</h4>
<p>yeah, let's go for check for the top-1000 and then think a bit more meanwhile about if we want a test run</p>



<a name="247956106"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/268952-edition%202021/topic/crater%20run/near/247956106" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Mara <a href="https://rust-lang.github.io/zulip_archive/stream/268952-edition-2021/topic/crater.20run.html#247956106">(Aug 02 2021 at 18:58)</a>:</h4>
<p>thanks!</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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